Salivary gland neoplasms as a late consequence of head and neck irradiation.

An increased occurrence of salivary tumors was observed in 1922 patients who received radiation to the tonsils and nasopharynx. Twenty-seven tumors, 19 benign and eight malignant, were found in this group as compared with an expected 0.2 malignant and less than 1 benign tumor. The latent period between the initial radiation treatment and diagnosis ranged from 7 to 32 years. After the first 15 years the incidence (77 cases/10(5) subjects/year) has remained constant and shows no indication of declining. Continued observation for salivary gland tumors is therefore indicated for subjects who received childhood irradiation.